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a(n) = phi(11^n+1), where phi is Euler's totient function (A000010).
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%I #12 Jan 04 2024 17:09:56

%S 1,4,60,432,7320,53680,803520,6495720,100874752,764738496,12756110400,

%T 89493288192,1568774615040,11278053084480,180228847518720,

%U 1310982643872000,22974417331646464,168479281019744640,2521788545778163200,20190830281379049600

%N a(n) = phi(11^n+1), where phi is Euler's totient function (A000010).

%H Max Alekseyev, <a href="/A366690/b366690.txt">Table of n, a(n) for n = 0..325</a>

%F a(n) = A000010(A034524(n)). - _Paul F. Marrero Romero_, Nov 10 2023

%t EulerPhi[11^Range[0,19] + 1] (* _Paul F. Marrero Romero_, Nov 10 2023 *)

%o (PARI) {a(n) = eulerphi(11^n+1)}

%Y Cf. A034524, A000010, A062308, A366685, A366686, A366687, A366689, A366689, A366716.

%K nonn

%O 0,2

%A _Sean A. Irvine_, Oct 16 2023